When Steve Coppell managed ­Reading he regarded cup runs as a busman's holiday, trivialites which were irrelevant to the serious business of league points. This would appear to apply even more so now, with the Championship side struggling to avoid relegation. Conversely, the presence of Reading in the last 16 of the FA Cup, having again beaten Premier League opposition, may prove a catalyst in restoring their ­players' confidence, starting with tomorrow's visit to Sheffield United.

True, this win in the fourth round did not have quite the impact of the one at Anfield in the third. If Liverpool were a scalp, Burnley, a soft touch away from Turf Moor, barely amounted to a hair follicle. Yet the match was won with the comparable drama of a late goal again scored by Gylfi Sigurdsson, the 20-year-old ­Icelander whose stoppage-time penalty had done for Rafael Benítez's team.

Sigurdsson is a midfielder-cum-winger but on Saturday he took his chance like an experienced centre-forward, getting in front of Kevin McDonald in the 87th minute to meet a dipping long ball from Andy Griffin and apply a sweet touch before turning to beat Brian Jensen with a shot of modest strength but perfectly judged angle.

Sigurdsson joined Reading in his early teens. "We were waiting for him to grow," said Brian McDermott, the caretaker manager, which made the youngster sound like a tomato plant. "He is getting bigger and has a real aura about him."

Had he not scored on Saturday, ­Sigurdsson would have been left to rue putting a free header wide after 71 minutes. ­McDermott was understandably noncommittal about his chances of a permanent job as a result of two wins in the FA Cup. The chairman, Sir John Madejski, will probably want to see evidence of his ability to turn things around in the ­Championship, where Reading are stuck in the bottom three and have not won for seven games.

Brian Laws, Burnley's new manager, insisted that "we desperately wanted to get through to the next round" but it took his team an age to find sufficient energy to apply serious pressure to Reading's goal. Even then they created fewer chances and came no closer to scoring than when David Edgar's header, bound for the top right-hand corner of the net, was kept out acrobatically by Adam Federici.

The last 20 minutes were more like a cut-and-thrust cup-tie, in sharp contrast to the first hour when at one point the Burnley fans chanted: "It feels like we're in church!" For the most part the occasion had all the fervour of deck quoits on the Mary Celeste.

• This article was amended on 27 January 2010. The original referred to the Marie Celeste. This has been corrected.